Construction industry is both one of the largest and one of the most dangerous industries in the United States. However, there is little literature on the different risk factors and risk groups within this industry. In this study we propose to do research on risk factors and risk groups in construction industry. Furthermore we will investigate the relation between working conditions and health in construction industry in a true longitudinal design, using an existing database. In the Netherlands, data is collected on a yearly basis on working conditions and health in construction industry. Construction workers have the opportunity to have a regular health checkup. The health checkup is performed on a voluntary basis, and at no cost to the employee. It consists of a physical exam (blood pressure, VO2-max, etc.) performed by the company health doctor and health nurse. When employees are invited to their health checkup, via a letter sent to their home address, they are asked to fill out a questionnaire. In the questionnaire, questions are asked about working conditions and health. All the activities the company health care services carry out for the construction industry are recorded in a computerized database. Only after the data has been recorded, are the company health services paid for the checkups. The computerized database (which is called VISA - a Dutch abbreviation for Activity Recording System Arbouw) includes data from the questionnaires filled out by the employees. These questionnaires are scanned and stored in a large database. Following this process, data from over 60,000 employees in the construction industry is collected every two years. To summarize, in the proposed study, we will use the longitudinal information in the database to evaluate risk factors and risk groups within construction industry and examine relations between working conditions and health in construction industry.